This application is a 371 of PCT/NO98/00288 filed Sep. 30, 1998.
The present invention concerns a method for mass transfer between gas and liquid or a chemical reaction with or without a catalyst between gas and liquid, comprising one or more process stages at each of which stripping gas or reaction gas is added. The invention is particularly well suited for use in connection with the deoxygenation of sea water which is to be injected into petroliferous formations beneath the sea bed as it is very compact and has a low weight.
Norwegian patent no. 158283 describes a system in which a circulating stripping gas, for example N2, is purified catalytically before being introduced into a mass transfer unit which may be in the form of static mixers, a serpentine pipe or a tower. These prior art solutions have, until today, been considered to be both effective and compact.
However, the present invention represents a mass transfer solution which is much more effective, more compact and lighter and cheaper than the prior art solutions.
The method in accordance with the present invention is characterized by one or more process stages at each of which one or more reactors are used in the form of driven dynamic mixers and at each of which gas is added at one or more locations so that the gas and the liquid move in a turbulent co-current through each mixer.
Moreover, the equipment in accordance with the present invention is characterized by one or more process stages at each of which one or more dynamic mixers are used and gas is added at one or more locations in connection with the mixers so that the gas and the liquid pass in a turbulent co-current flow through the mixers.
The reason for the very effective mass transfer with the present invention is the design of the dynamic mixers which ensure the formation of very small gas bubbles, which produces a relatively large contact surface between the gas and the liquid and effective agitation, together with a virtual xe2x80x9cpiston currentxe2x80x9d through the mixers.
As the dynamic mixers in a multi-stage system in accordance with the present invention may be placed horizontally and above one another, the design of a multi-stage system is much simpler than that of the prior art solutions as:
intermediate pressure pumps are eliminated,
gas compressors can be replaced by simple blowers,
the energy consumption is reduced,
the volume and weight of the equipment are reduced considerably,
the height, width and length of the installation can be selected to a greater degree, which makes the installation more flexible in terms of design.